Reactive force generation device of clutch-by-wire system and clutch lever device

ABSTRACT

A reactive force generation device ( 130 ) of clutch-by-wire system is a reactive force generation device which generates a reactive force on a clutch lever ( 51 ), and includes a piston structure in which an air bleeding hole ( 139 ) is provided, and a contact member ( 133 ) which is in contact with the clutch lever ( 51 ) and in which the air bleeding hole  139  is formed.

TECHNICAL FIELD

The present invention relates to a reactive force generation device of aclutch-by-wire system, and a clutch lever device.

Priority is claimed on Japanese Patent Application No. 2018-151509,filed Aug. 10, 2018 and Japanese Patent Application No. 2019-036015,filed Feb. 28, 2019, the content of which is incorporated herein byreference.

BACKGROUND ART

Conventionally, there is a clutch-by-wire system which electricallyconnects a clutch lever to a clutch device. For example, theclutch-by-wire system includes an actuator which drives the clutchdevice, an operation amount detection unit which detects an operationamount of the clutch lever, and an electronic control unit whichcontrols an operation of the actuator on the basis of a detection valueof the operation amount detection unit.

As the clutch-by-wire system, there is one including a mechanism forapplying an operation reactive force to the clutch lever in order toproduce an operation load of a conventional clutch lever mechanicallyconnected to the clutch device by hydraulic pressure, a cable or thelike (refer to, for example, Patent Literature 1). In Patent Literature1, a transmission device including a clutch lever, and a plurality ofcoil springs which gradually change a rate of increase of the operationreactive force of the clutch lever using an action of respective biasingforces thereof in a stepwise manner is disclosed. This transmissiondevice has a constitution in which the coil springs are disposed in alever cylinder, and a piston linked to the clutch lever is biased by thecoil springs.

CITATION LIST Patent Literature

[Patent Literature 1]

Japanese Unexamined Patent Application, First Publication No. 2013-57404

SUMMARY OF INVENTION Technical Problem

Incidentally, when a reactive force generation device which generates anoperation reactive force of the clutch lever has a piston structure asin the above-described related art, an air bleeding hole through whichair enters and exits according to volume changes when the piston movesmay be provided. However, foreign substances such as water or dust mayenter the inside of the piston structure through the air bleeding hole,and performance in the function of the reactive force generation devicemay be deteriorated.

Therefore, the present invention provides a reactive force generationdevice of a clutch-by-wire system and a clutch lever device capable ofcurbing entry of foreign substances into a piston structure.

Solution to Problem

(1) A reactive force generation device of a clutch-by-wire systemaccording to an aspect of the present invention is a reactive forcegeneration device (130) which generates a reactive force on a clutchlever (51), and includes a piston structure in which an air bleedinghole (139) is provided, and a contact member (133) which is in contactwith the clutch lever (51) and in which the air bleeding hole 139 isformed.

With such a constitution, the clutch lever is located in the vicinity ofthe air bleeding hole by forming the air bleeding hole in the contactmember which comes into contact with the clutch lever. Therefore, theair bleeding hole is disposed at a position at which it is difficult toaccess from the outside because it is obstructed by the clutch lever.Therefore, it is possible to curb entry of foreign substances such aswater and dust into the piston structure through the air bleeding hole .

(2) In the reactive force generation device of the clutch-by-wire systemdescribed in (1), the contact member (133) may have a contact surface(138) which comes into contact with the clutch lever (51) and in whichthe air bleeding hole (139) opens, and the contact surface (138) mayface the rear of a vehicle.

With such a constitution, since the air bleeding hole opens to the rearof the vehicle, it is possible to curb entry of foreign substances intothe piston structure through the air bleeding hole when the vehicle istraveling, as compared with a constitution in which the air bleedinghole opens a front of the vehicle.

(3) In the reactive force generation device of the clutch-by-wire systemdescribed in (1) or (2), the contact member (133) may have a contactsurface (138) which comes into contact with a roller (80) of the clutchlever (51) and in which the air bleeding hole (139) opens, and theroller (80) may roll on the contact surface (138) according to anoperation of the clutch lever (51).

With such a constitution, the air bleeding hole is provided at aposition at which it is closer to the clutch lever. Therefore, the airbleeding hole is disposed at a position at which it is more difficult toaccess from the outside. Therefore, it is possible to curb the entry offoreign substances such as water and dust into the piston structurethrough the air bleeding hole.

(4) In the reactive force generation device of the clutch-by-wire systemdescribed in (3), the air bleeding hole (139) may be formed in a regionin which the roller (80) comes into contact.

With such a constitution, since the air bleeding hole is blocked by theroller when the clutch lever is operated, it is possible to curb theentry of foreign substances into the piston structure through the airbleeding hole when the clutch lever is operated.

(5) In the reactive force generation device of the clutch-by-wire systemdescribed in any one of (1) to (4), a labyrinth structure whichobstructs a flow of a fluid through the air bleeding hole (139) may beformed on the contact member (133).

With such a constitution, it is possible to effectively curb the entryof foreign substances such as water and dust into the piston structurethrough the air bleeding hole.

(6) In the reactive force generation device of the clutch-by-wire systemdescribed in (5), the labyrinth structure may have a flow passage (142)which communicates with the air bleeding hole (139) and extendsspirally.

With such a constitution, for example, as compared with a constitutionin which the flow passage extends linearly, it is possible toeffectively curb advance of foreign substances, such as water or dustwhich has entered the air bleeding hole, through the flow passage.Therefore, it is possible to curb the entry of foreign substances intothe piston structure.

(7) In the reactive force generation device of the clutch-by-wire systemdescribed in any one of (1) to (6), a holding member (131) which holdsthe contact member (133) and constitutes a piston structure togetherwith the contact member (133), a coil spring (151) which is interposedbetween the contact member (133) and the holding member (131) andpresses the contact member (133) at a first end portion thereof, and anadjuster (360) which is provided on the holding member (131) and causesa second end portion of the coil spring (151) to come closer to andseparate from the first end portion may be included.

With such a constitution, the adjuster can change a length between bothend portions of the coil spring to adjust a force for pressing thecontact member. Therefore, it is possible to provide the reactive forcegeneration device which can freely change the reactive force applied tothe clutch lever.

(8) A clutch lever device according to an aspect of the presentinvention is a clutch lever device which includes the reactive forcegeneration device (130) of the clutch-by-wire system described in anyone of (1) to (7), including a clutch lever (51) which rotates around arotation axis (O) and to which a reactive force is applied by thereactive force generation device (130), and a lever holder (210) whichrotatably supports the clutch lever (51) and surrounds a contact portionin which the clutch lever (51) and the contact member (133) come intocontact with each other, wherein an opening portion (211) into which theclutch lever (51) is inserted is formed in the lever holder (210), theclutch lever (51) has an facing surface (71 a) which faces an openingedge (211 a) of the opening portion (211) in a direction orthogonal tothe rotation axis (O), and the facing surface (71 a) continuously facesthe opening edge (211 a) of the opening portion (211) from a state inwhich the clutch lever (51) is not being operated to a state in whichthe clutch lever (51) is being operated and extends in an arc shapecentered on the rotation axis (O) when seen in a direction in which therotation axis (O) extends.

With such a constitution, a distance of a gap between the clutch leverand the opening edge of the lever holder can be kept constant regardlessof an amount of operation of the clutch lever. Thus, it is possible tocurb easy entry of foreign substances into the lever holder by operatingthe clutch lever as the gap between the clutch lever and the openingedge of the opening portion changes. Therefore, it is possible to curboccurrence of defects such as biting of foreign substances.

(9) In the clutch lever device described in (8), the facing surface (71a) may face a front opening edge (117 a) of the opening portion (211).

With such a constitution, it is possible to effectively curb the entryof foreign substances or the like approaching the lever holder from thefront side into the lever holder when the vehicle is traveling.

(10) A clutch lever device according to an aspect of the presentinvention is a clutch lever device which includes the reactive forcegeneration device (130) of the clutch-by-wire system described in anyone of (1) to (7), including a clutch lever (51) which rotates around arotation axis (O) and to which a reactive force is applied by thereactive force generation device (130), and a lever holder (210) whichrotatably supports the clutch lever (51) and surrounds a contact portionin which the clutch lever (51) and the contact member (133) come intocontact with each other, wherein the lever holder (210) includes a lowersurface (210 a) which defines from below a space in which a contactportion in which the clutch lever (51) and the contact member (133) comeinto contact with each other is disposed, a communication portion (212)which allows communication between an inside and an outside the leverholder (210) is formed in the lower surface (210 a), and the lowersurface (210 a) is inclined to descend toward the communication portion(212).

With such a constitution, foreign substances which have entered thespace in which the contact portion in which the clutch lever and thecontact member comes into contact with each other is disposed can besmoothly guided to the communication portion by an inclination of thelower surface of the lever holder. Therefore, even when the foreignsubstances have entered the inside of the lever holder, the foreignsubstances can be effectively discharged through the communicationportion, and occurrence of defects such as the biting of the foreignsubstances can be curbed.

Advantageous Effects of Invention

According to the reactive force generation device of the clutch-by-wiresystem and the clutch lever device, it is possible to curb entry offoreign substances into a piston structure.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a left side view of a motorcycle of a first embodiment.

FIG. 2 is a schematic explanatory view of a clutch operation systemincluding a clutch actuator.

FIG. 3 is a plan view of the surroundings of a clutch lever device ofthe first embodiment.

FIG. 4 is a perspective view of a clutch lever device of the firstembodiment when seen from above and in front.

FIG. 5 is a perspective view of the clutch lever device of the firstembodiment when seen from below and in front.

FIG. 6 is a cross-sectional view of the clutch lever device of the firstembodiment when seen from above.

FIG. 7 is an enlarged cross-sectional view of the clutch lever device ofthe first embodiment.

FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 3.

FIG. 9 is an operation explanatory view of the clutch lever device ofthe first embodiment.

FIG. 10 is a cross-sectional view of a clutch lever device of a secondembodiment when seen from above.

FIG. 11 is a perspective view of the clutch lever device of the secondembodiment when seen from above and behind.

FIG. 12 is a cross-sectional view of a portion corresponding to lineXII-XII of FIG. 10.

FIG. 13 is a cross-sectional view of a clutch lever device of the secondembodiment when seen from above.

FIG. 14 is a perspective view of the clutch lever device of the secondembodiment when seen from above and in front.

FIG. 15 is an enlarged cross-sectional view of a clutch lever device ofa third embodiment.

Description of Embodiments

Hereinafter, embodiments of the present invention are described withreference to the drawings. In the following description, directions suchas forward, rearward, right and left are the same as those in a vehicledescribed below unless otherwise noted. Also, in the drawings used forthe following description, an arrow FR indicating a front of thevehicle, an arrow LH indicating a left side of the vehicle, and an arrowUP indicating an upper side of the vehicle are shown at appropriatepositions.

First Embodiment

A motorcycle of a first embodiment will be described with reference toFIGS. 1 to 9.

Overall Constitution of Vehicle

FIG. 1 is a left side view of a motorcycle according to a firstembodiment.

As shown in FIG. 1, this embodiment is applied to a motorcycle 1 whichis a saddle-riding type vehicle. A front wheel 2 of the motorcycle 1 issupported by lower end portions of a pair of right and left front forks3. An upper portion of the right and left front forks 3 is supported bya head pipe 7 of a front end portion of a vehicle body frame 6 via asteering stem 4. A steering handle bar 5 is installed on a top bridge ofthe steering stem 4. A grip portion 5 a gripped by a driver is providedon each of right and left outer portions of the handle bar 5. In theembodiment, it is assumed that the grip portion 5 a extends in a vehiclewidth direction (a right and left direction). However, the grip portion5 a may extend obliquely with respect to the vehicle width direction.

The vehicle body frame 6 includes the head pipe 7, a main tube 8 whichextends downward and rearward from the head pipe 7 at a center in thevehicle width direction, right and left pivot frames 9 which extenddownward from a rear end portion of the main tube 8, and a seat frame 10which extends rearward from the main tube 8 and the right and left pivotframes 9. A front end portion of a swing arm 11 is pivotally supportedby the right and left pivot frame 9 to be swingable. A rear wheel 12 ofthe motorcycle 1 is supported at a rear end portion of the swing arm 11.

A fuel tank 18 is supported above the right and left main tubes 8. Afront seat 19 and a rear seat cover 19 a are supported above the seatframe 10. The front seat 19 and the rear seat cover 19 a are disposed atthe front and the rear behind the fuel tank 18. The surroundings of theseat frame 10 are covered with a rear cowl 10 a. A power unit PU whichis a prime mover of the motorcycle 1 is suspended below the right andleft main tubes 8. The power unit PU is linked to the rear wheel 12 viaa chain type transmission mechanism, for example.

The power unit PU integrally has an engine 13 located at a front portionand a transmission 21 located at a rear portion. The engine 13 is, forexample, a multi-cylinder engine in which a rotation axis of acrankshaft 14 extends in the vehicle width direction. The engine 13includes cylinders 16 which stand upward at a front portion of acrankcase 15. A rear portion of the crankcase 15 is a transmission case17 which accommodates the transmission 21. The transmission 21 is astepped transmission.

FIG. 2 is a schematic explanatory view of a clutch operation systemincluding a clutch actuator.

As shown in FIGS. 1 and 2, a clutch device 26 operated by a clutchactuator 30 is disposed in the transmission 21. The clutch device 26 is,for example, a wet type multi-disk clutch and is a so-called normallyopen clutch. That is, the clutch device 26 is brought into a connectedstate in which power can be transmitted due to hydraulic pressure supplyfrom the clutch actuator 30 and then returns to a disconnected state inwhich power transmission is not possible when the hydraulic pressuresupply from the clutch actuator 30 is cut off.

Rotational power of the crankshaft 14 is transmitted to the transmission21 via the clutch device 26. A drive sprocket 27 of the chain typetransmission mechanism is installed in the transmission 21.

Transmission System

Here, a transmission system of the motorcycle 1 includes the clutchactuator 30, an electronic control unit (ECU) 40, and a clutch leverdevice 50.

As shown in FIG. 2, as an operation of the clutch actuator 30 iscontrolled by the ECU 40, a fluid pressure by which the clutch device 26is connected or disconnected can be controlled. The clutch actuator 30includes an electric motor 32 (hereinafter, simply referred to as amotor 32) as a drive source, and a master cylinder 31 driven by themotor 32. The clutch actuator 30 constitutes an integral clutch controlunit 30A together with a hydraulic circuit device 33 provided betweenthe master cylinder 31 and a hydraulic supply/discharge port 30 p.

The ECU 40 calculates a target value (a target hydraulic pressure) ofthe hydraulic pressure to be supplied to a slave cylinder 28 to connector disconnect the clutch device 26 on the basis of a detection value ofa rotation sensor 160 and a preset calculation program which will bedescribed later. The ECU 40 controls the clutch control unit 30A so thatthe hydraulic pressure (a slave hydraulic pressure) on the slavecylinder 28 side which is detected by a downstream side hydraulicpressure sensor 38 approaches the target hydraulic pressure.

The master cylinder 31 causes stroking of a piston 31 b in a cylinderbody 31 a due to driving of the motor 32 so that working oil in thecylinder body 31 a can be supplied to and discharged from the slavecylinder 28. In the drawing, a reference numeral 35 indicates aconversion mechanism as a ball screw mechanism, a reference numeral 34indicates a transmission mechanism extending across the motor 32 and theconversion mechanism 35, and a reference numeral 31 e indicates areservoir connected to the master cylinder 31.

The hydraulic circuit device 33 has a valve mechanism (a solenoid valve36) for opening or blocking an intermediate portion of a main oilpassage 33 m extending from the master cylinder 31 to the clutch device26 side (the slave cylinder 28 side). The main oil passage 33 m of thehydraulic circuit device 33 can be divided into an upstream side oilpassage 33 a located on the master cylinder 31 side of the solenoidvalve 36 and a downstream side oil passage 33 b located on the slavecylinder 28 side of the solenoid valve 36. The hydraulic circuit device33 further includes a bypass oil passage 33 c which bypasses thesolenoid valve 36 and allows communication between the upstream side oilpassage 33 a and the downstream side oil passage 33 b.

The solenoid valve 36 is a so-called normally open valve. A one-wayvalve 33 c 1 which allows the working oil to flow only in a directionfrom the upstream side to the downstream side is provided in the bypassoil passage 33 c. An upstream side hydraulic pressure sensor 37 fordetecting a hydraulic pressure of the upstream side oil passage 33 a isprovided on the upstream side of the solenoid valve 36. The downstreamside hydraulic pressure sensor 38 for detecting a hydraulic pressure ofthe downstream side oil passage 33 b is provided on the downstream sideof the solenoid valve 36.

As shown in FIG. 1, the clutch control unit 30A is accommodated in therear cowl 10 a, for example. The slave cylinder 28 is installed on theleft side of the rear part of the crankcase 15. The clutch control unit30A and the slave cylinder 28 are connected via a hydraulic pipe 33 e(refer to FIG. 2).

As shown in FIG. 2, when the hydraulic pressure is supplied from theclutch actuator 30, the slave cylinder 28 operates the clutch device 26such that it is brought into the connected state. When the hydraulicpressure supply is cut off, the slave cylinder 28 returns the clutchdevice 26 to the disconnected state.

In order to maintain the clutch device 26 in the connected state, it isnecessary to continue the hydraulic pressure supply, but electric poweris consumed correspondingly. Therefore, the solenoid valve 36 isprovided in the hydraulic circuit device 33 of the clutch control unit30A, and the solenoid valve 36 is closed after the hydraulic pressure issupplied to the clutch device 26 side. Accordingly, energy consumptionis minimized by maintaining the hydraulic pressure supplied to theclutch device 26 side and supplementing the hydraulic pressure accordingto a pressure drop (recharging according to a leakage amount).

Overall Constitution of Clutch Lever Device

FIG. 3 is a plan view of the surroundings of the clutch lever device ofthe first embodiment.

As shown in FIG. 3, the clutch lever device 50 is installed on thehandle bar 5 to be parallel with the left grip portion 5 a. The clutchlever device 50 serves as an operator for transmitting a clutchoperation request signal to the ECU 40 without a mechanical connectionwith the clutch device 26 using a cable, a hydraulic pressure, or thelike. That is, the motorcycle 1 employs a clutch-by-wire system in whichthe clutch device 26 and a clutch lever 51 which will be described laterare electrically connected.

FIG. 4 is a perspective view of the clutch lever device of the firstembodiment when seen from above and in front. FIG. 5 is a perspectiveview of the clutch lever device of the first embodiment when seen frombelow and in front.

As shown in FIGS. 3 to 5, the clutch lever device 50 includes a clutchlever 51 which is operated by an occupant to rotate around a rotationaxis O, a lever holder 110 which rotatably supports the clutch lever 51,a reactive force generation device 130 which has a piston structure andgenerates an operation reactive force on the clutch lever 51, and arotation sensor 160 which detects a rotation angle of the clutch lever51.

In the following description of the clutch lever device 50, a state inwhich the clutch lever 51 is not being operated (a state shown in FIGS.3 to 8) will be described unless otherwise noted. Further, regarding arotational position of the clutch lever 51, a position of the state inwhich the clutch lever 51 is not being operated is referred to as apre-operation position. Further, regarding a circumferential directionaround the rotation axis O, a direction in which the clutch lever 51rotates from the pre-operation position when the clutch lever 51 isoperated is defined as an operation direction G. Further, in thefollowing description, a direction in which the rotation axis O extendsis referred to as an axial direction. The axial direction is a directionalong a vertical direction and is at least a direction inclined withrespect to a horizontal direction. In the embodiment, the axialdirection is the vertical direction.

Hereinafter, the clutch lever device 50 will be described in detail.

Lever Holder

The lever holder 110 is installed on the inner side (the right side) inthe vehicle width direction with respect to the left grip portion 5 a ofthe handle bar 5. The lever holder 110 includes a fixed portion 111which is fixed to the handle bar 5, a lever support portion 113 whichextends from the fixed portion 111 to support the clutch lever 51, apiston holding portion 117 which is connected to the fixed portion 111and the lever support portion 113 and holds a piston 133 (refer to FIG.6) of the reactive force generation device 130, and a rotation sensorholding portion 124 (refer to FIG. 8) which holds the rotation sensor160.

As shown in FIG. 3, the fixed portion 111 is fixed to the handle bar 5on the side opposite to the left grip portion 5 a with a switch box 5 binterposed therebetween. The fixed portion 111 includes a front halfbody fitted to a front half peripheral surface of the handle bar 5, anda rear half body fitted to a rear half peripheral surface of the handlebar 5. The front half body and the rear half body of the fixed portion111 are connected to each other by bolts to sandwich the handle bar 5.

As shown in FIGS. 3 to 5, the lever support portion 113 extends from thefixed portion 111 in a direction orthogonal to the axial direction. Thelever support portion 113 includes an upper support portion 114 and alower support portion 115 which extend parallel to each other with aninterval therebetween in the axial direction to sandwich a base of theclutch lever 51. The upper support portion 114 and the lower supportportion 115 extend forward from the fixed portion 111, then are bent andextend forward and outward in the vehicle width direction when seen inthe vertical direction. The lower support portion 115 extends longerthan the upper support portion 114. A through hole 113 a (refer to FIG.8) coaxial with the rotation axis O is formed in the upper supportportion 114 and the lower support portion 115.

The piston holding portion 117 is formed in a cylindrical shape andextends inward from the lever support portion 113 in the vehicle widthdirection. Hereinafter, a direction in which the piston holding portion117 extends from the lever support portion 113 is defined as a firstdirection L1, and a direction opposite to the first direction L1 isdefined as a second direction L2. In the embodiment, the first directionL1 is a direction which is directed forward with respect to inward inthe vehicle width direction. Further, the second direction L2 is adirection which is directed rearward with respect to outward in thevehicle width direction.

FIG. 6 is a cross-sectional view of the clutch lever device of the firstembodiment when seen from above.

As shown in FIGS. 3 and 6, the piston holding portion 117 is coupled tothe fixed portion 111, the upper support portion 114, and the lowersupport portion 115. An end portion of the piston holding portion 117 inthe second direction L2 opens to a space between the upper supportportion 114 and the lower support portion 115. The lever holder 110surrounds a contact portion in which the clutch lever 51 and the piston133 of the reactive force generation device 130 come into contact witheach other by the lever support portion 113 and the piston holdingportion 117. An end portion of the piston holding portion 117 in thefirst direction L1 is closed.

As shown in FIG. 6, the piston holding portion 117 includes a firsttubular portion 118 and a second tubular portion 119. The first tubularportion 118 is a portion of the piston holding portion 117 in the seconddirection L2. The first tubular portion 118 is connected to the fixedportion 111, the upper support portion 114 (refer to FIG. 3), and thelower support portion 115. The second tubular portion 119 is a portionof the piston holding portion 117 in the first direction L1. The secondtubular portion 119 is connected to an end portion of the first tubularportion 118 in the first direction L1. The second tubular portion 119 isformed in a bottomed tubular shape which opens into a space inside thefirst tubular portion 118. An inner peripheral surface of the secondtubular portion 119 has a smaller diameter than an inner peripheralsurface of the first tubular portion 118. The second tubular portion 119forms a cylinder 131 of the reactive force generation device 130(details will be described later).

FIG. 7 is an enlarged cross-sectional view of the clutch lever device ofthe first embodiment.

As shown in FIG. 7, a first stepped surface 120, a first groove 121, anda second groove 122 are formed on an inner peripheral surface of thepiston holding portion 117. The first stepped surface 120 is providedbetween the inner peripheral surface of the first tubular portion 118and the inner peripheral surface of the second tubular portion 119. Thefirst stepped surface 120 is an end surface of the second tubularportion 119 in the second direction L2. The first stepped surface 120 isdirected in the second direction L2. The first groove 121 and the secondgroove 122 are provided near an end portion of the inner peripheralsurface of the first tubular portion 118 in the first direction L1. Thefirst groove 121 and the second groove 122 extend in an annular shapeover the entire circumference of the first tubular portion 118 in thecircumferential direction. The first groove 121 is disposed at aninterval with respect to the first stepped surface 120. The secondgroove 122 is disposed at an interval with respect to the first groove121 and disposed on the side opposite to the first stepped surface 120with the first groove 121 interposed therebetween. That is, the secondgroove 122 is formed in the second direction L2 with respect to thefirst groove 121.

FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. 3.

As shown in FIG. 8, the rotation sensor holding portion 124 is providedon the lever support portion 113. The rotation sensor holding portion124 is provided on a lower surface of the lower support portion 115 ofthe lever support portion 113. The rotation sensor holding portion 124includes a recessed portion 124 a which is recessed upward. A lower endportion of the through hole 113 a opens into the recessed portion 124 a.A part of the rotation sensor 160 is inserted into the recessed portion124 a from below.

Reactive Force Generation Device

As shown in FIG. 7, the reactive force generation device 130 has apiston structure and elastically expands and contracts in the firstdirection L1 and the second direction L2 to apply an operation reactiveforce to the clutch lever 51. The reactive force generation device 130includes a cylinder (holding member) 131 and a piston (a contact member)133 which constitute the piston structure, an intermediate tube 144, anda spring (a coil spring) 151. The cylinder 131 is the second tubularportion 119 of the piston holding portion 117. The piston 133 isinserted inside the cylinder 131. The intermediate tube 144 is disposedbetween an inner peripheral surface of the cylinder 131 and an outerperipheral surface of the piston 133. The spring 151 is interposedbetween the cylinder 131 and the piston 133.

The piston 133 is a member with which the clutch lever 51 comes intocontact. The piston 133 is formed in a bottomed cylindrical shape and isdisposed coaxially with the cylinder 131. An end portion of the piston133 in the first direction L1 opens to the space inside the cylinder131. A diameter of an inner peripheral surface of the piston 133gradually increases from an end portion thereof in the second directionL2 toward the first direction L1. The piston 133 includes a largediameter portion 134, a medium diameter portion 135, and a smalldiameter portion 136.

The large diameter portion 134 includes an end portion of the piston 133in the first direction L1. The large diameter portion 134 is alwaysdisposed inside the cylinder 131 regardless of an expansion/contractionstate of the reactive force generation device 130. An outer diameter ofthe large diameter portion 134 is smaller than an inner diameter of thecylinder 131. The large diameter portion 134 is formed to be smallerthan the cylinder 131 in a direction parallel to the first direction L1.Thus, the large diameter portion 134 can move inside the cylinder 131 inboth directions of the first direction L1 and the second direction L2.

The medium diameter portion 135 is adjacent to the large diameterportion 134. The medium diameter portion 135 is connected to an endportion of the large diameter portion 134 in the second direction L2. Aninner diameter of the medium diameter portion 135 is smaller than aninner diameter of the large diameter portion 134. An outer diameter ofthe medium diameter portion 135 is smaller than the outer diameter ofthe large diameter portion 134. A second stepped surface 133 a directedin the second direction L2 is formed between an outer peripheral surfaceof the medium diameter portion 135 and an outer peripheral surface ofthe large diameter portion 134.

The small diameter portion 136 includes an end portion of the piston 133in the second direction L2. The small diameter portion 136 is adjacentto the medium diameter portion 135. The small diameter portion 136 isconnected to an end portion of the medium diameter portion 135 in thesecond direction L2. The small diameter portion 136 has a peripheralwall 136 a and a bottom wall 136 b. An inner diameter of the peripheralwall 136 a of the small diameter portion 136 is smaller than an innerdiameter of the medium diameter portion 135. A third stepped surface 133b directed in the first direction L1 is formed between an innerperipheral surface of the peripheral wall 136 a of the small diameterportion 136 and an inner peripheral surface of the medium diameterportion 135. A flange 137 which protrudes outward in a radial directionis formed at an end portion of the small diameter portion 136 in thesecond direction L2. The flange 137 extends over the entirecircumference of the small diameter portion 136 in the circumferentialdirection. A third groove 137 a is formed in an outer peripheral surfaceof the flange 137. The third groove 137 a extends in an annular shapeover the entire circumference of the small diameter portion 136 in thecircumferential direction.

A surface of the flange 137 directed in the second direction L2constitutes a tip end surface (a contact surface) 138 of the piston 133together with a surface of the bottom wall 136 b directed in the seconddirection L2. The tip end surface 138 of the piston is a flat surface.Since the second direction L2 is a direction directed rearward withrespect to outward in the vehicle width direction, the tip end surface138 of the piston is directed rearward with respect to outward in thevehicle width direction. The clutch lever 51 comes into contact with thetip end surface 138 of the piston 133. An air bleeding hole 139 isformed in the bottom wall 136 b of the small diameter portion 136. Theair bleeding hole 139 passes through the center of the bottom wall 136 band allows communication between the inside and the outside of thepiston 133. The air bleeding hole 139 opens into a space surrounded bythe lever holder 110 on the tip end surface 138 of the piston 133 (referto FIG. 6).

A labyrinth structure which obstructs a flow of a fluid through the airbleeding hole 139 is formed in the piston 133. The labyrinth structureis formed by the small diameter portion 136 and a labyrinth member 141.The labyrinth member 141 is disposed inside the small diameter portion136. The labyrinth member 141 is formed in a cylindrical shape whichmatches an internal shape of the small diameter portion 136. Thelabyrinth member 141 is fixed to the small diameter portion 136, forexample, by being fitted inside the small diameter portion 136. Thelabyrinth structure includes a flow passage 142 which allowscommunication between the inside of the medium diameter portion 135 andthe air bleeding hole 139 between an outer surface of the labyrinthmember 141 and an inner surface of the small diameter portion 136. Theflow passage 142 is formed by a first labyrinth groove 142 a and asecond labyrinth groove 142 b formed on the outer surface of thelabyrinth member 141, and the inner surface of the small diameterportion 136.

The first labyrinth groove 142 a is formed in an end surface of thelabyrinth member 141 in the second direction L2. The first labyrinthgroove 142 a extends from a position facing the air bleeding hole 139 toa position facing the inner peripheral surface of the peripheral wall136 a of the small diameter portion 136. The second labyrinth groove 142b is formed in an outer peripheral surface of the labyrinth member 141.The second labyrinth groove 142 b is connected to an outer end portionof the first labyrinth groove 142 a in the radial direction. The secondlabyrinth groove 142 b extends spirally in the first direction L1 froman end edge of the labyrinth member 141 in the second direction L2 to anend edge of the labyrinth member 141 in the first direction L1. Thus,the flow passage 142 extends spirally around a center axis of the piston133.

The intermediate tube 144 is formed in a cylindrical shape of which bothend portions are open and is disposed coaxially with the piston 133. Theintermediate tube 144 is airtightly fitted inside the cylinder 131. Theintermediate tube 144 may be in sliding contact with the innerperipheral surface of the cylinder 131 or may be press-fitted into theinner peripheral surface of the cylinder 131. An inner peripheralsurface of the intermediate tube 144 is airtightly in sliding contactwith the outer peripheral surface of the large diameter portion 134 ofthe piston 133. The intermediate tube 144 is formed to be larger thanthe large diameter portion 134 of the piston 133 in a direction parallelto the first direction L1.

The piston 133 and the intermediate tube 144 are held inside the pistonholding portion 117 by a snap ring 145 and a restricting ring 146. Thesnap ring 145 is fitted in the first groove 121 of the piston holdingportion 117. The restricting ring 146 is formed in an annular shape andis disposed between the snap ring 145 and the first stepped surface 120of the piston holding portion 117. The restricting ring 146 isrestricted from moving in the second direction L2 by the snap ring 145and is restricted from moving in the first direction L1 by the firststepped surface 120.

The medium diameter portion 135 of the piston 133 is inserted inside thesnap ring 145 and the restricting ring 146. An inner diameter of therestricting ring 146 is smaller than the outer diameter of the largediameter portion 134 of the piston 133. Therefore, the restricting ring146 can come into contact with an end edge of the intermediate tube 144in the second direction L2 and the second stepped surface 133 a of thepiston 133 from the second direction L2. Additionally, the restrictingring 146 restricts coming out of the intermediate tube 144 and the largediameter portion 134 of the piston 133 from the inside of the cylinder131 in the second direction L2.

The spring 151 is disposed between the piston 133 and the cylinder 131.The spring 151 biases the piston 133 with respect to the cylinder 131 inthe second direction L2. The spring 151 is a compression coil spring andis disposed coaxially with the piston 133. The spring 151 is formed tohave a diameter smaller than an inner peripheral surface of the mediumdiameter portion 135 of the piston 133 and is disposed from the insideof the cylinder 131 to the inside of the piston 133. A first seat 152 isinstalled on an end portion (a second end portion) of the spring 151 inthe first direction L1. The spring 151 presses the cylinder 131 via thefirst seat 152 at an end portion thereof in the first direction L1. Thefirst seat 152 includes a tubular portion 152 a which is inserted insidethe end portion of the spring 151 in the first direction L1 and a flangeportion 152 b which protrudes radially outward from an end portion ofthe tubular portion 152 a in the first direction L1. The flange portion152 b covers the end portion of the spring 151 in the first direction L1from the first direction L1. The flange portion 152 b is interposedbetween the end portion of the spring 151 in the first direction L1 andthe bottom wall of the cylinder 131. A second seat 153 is installed onan end portion (a first end portion) of the spring 151 in the seconddirection L2. The spring 151 presses the cylinder 133 via the secondseat 153 at an end portion thereof in the second direction L2. Thesecond seat 153 is formed in the same manner as the first seat 152 andis interposed between the end portion of the spring 151 in the seconddirection L2 and the third stepped surface 133 b of the piston 133.

A packing 155 is disposed between the piston holding portion 117 and thereactive force generation device 130. The packing 155 is a flexiblesheet-like member. The packing 155 is formed in an annular shape whenseen from the second direction L2. An outer peripheral portion of thepacking 155 is airtightly fitted to the second groove 122 of the pistonholding portion 117. An inner peripheral portion of the packing 155 isairtightly fitted to the third groove 137 a of the piston 133. Thus, thepacking 155 covers a sliding portion of the piston 133 from the seconddirection L2.

Clutch Lever

As shown in FIG. 3, the clutch lever 51 is a clutch operator operated byan occupant.

The clutch lever 51 is disposed in front of the left grip portion 5 a.

As shown in FIG. 6, the clutch lever 51 includes a lever body 60 whichis touched and operated by the occupant, a knocker 70 which is providedseparately from the lever body 60, engages with the lever body 60 androtates together with the lever body 60, and a support shaft 90 which isdisposed coaxially with the rotation axis O and rotates around therotation axis O together with the lever body 60 and the knocker 70.

As shown in FIGS. 6 and 8, the knocker 70 is disposed between the uppersupport portion 114 and the lower support portion 115 of the leversupport portion 113. The knocker 70 is provided with respect to thelever support portion 113 to be rotatable around the rotation axis O.The knocker 70 is formed to have a U-shaped cross section which opens ina predetermined direction orthogonal to the axial direction and intowhich a rotation base portion 61 of the lever body 60 which will bedescribed later is inserted. The knocker 70 engages with the lever body60 at a first location in the predetermined direction with respect tothe rotation axis O and engages with the reactive force generationdevice 130 at a second position in a direction opposite to thepredetermined direction with respect to the rotation axis O. The knocker70 includes a base portion 71 supported by the support shaft 90, a firstarm 74 and a second arm 77 which extend from the base portion 71, and aroller 80 supported by the first arm 74.

As shown in FIG. 8, a support shaft insertion hole 72 into which thesupport shaft 90 is inserted is formed in the base portion 71. Thesupport shaft insertion hole 72 passes through the base portion 71 alongthe rotation axis O. The support shaft insertion hole 72 is formed in acircular shape when seen in the axial direction. The support shaftinsertion hole 72 is splined so that the knocker 70 and the supportshaft 90 can rotate integrally.

As shown in FIG. 6, the first arm 74 extends rearward and inward in thevehicle width direction from the base portion 71 when seen in thevertical direction. The first arm 74 extends from the base portion 71 ina direction orthogonal to the axial direction. A tip of the first arm 74is provided to face the tip end surface 138 of the piston 133. The tipof the first arm 74 is formed in a bifurcated shape branching on bothsides in the axial direction and rotatably supports the roller 80between two branches (refer to FIG. 8). The roller 80 is rotatablyprovided around an axis parallel to the rotation axis O. The roller 80is in contact with the tip end surface 138 of the piston 133. The roller80 is in contact with the tip end surface 138 of the piston 133 from theupstream side in an operation direction G. Accordingly, the knocker 70engages with the reactive force generation device 130. As the knocker 70rotates, the roller 80 rolls on the tip end surface 138 of the piston133 to pass over the air bleeding hole 139. That is, the air bleedinghole 139 is formed in a region of the piston 133 with which the roller80 comes into contact.

The second arm 77 extends from the base portion 71 on the side oppositeto the first arm 74. That is, the second arm 77 extends forward andoutward in the vehicle width direction from the base portion 71 whenseen in the vertical direction. The second arm 77 extends from the baseportion 71 in a direction orthogonal to the axial direction.

As shown in FIGS. 6 and 8, a main body accommodating portion 78 in whichthe rotation base portion 61 of the lever body 60 is accommodated isformed in the knocker 70. The main body accommodating portion 78 is arecessed portion formed in a front surface of the knocker 70. The mainbody accommodating portion 78 is recessed rearward and opens forward ina direction orthogonal to the axial direction. Thus, as described above,the knocker 70 is formed in a U-shaped cross section which opens in thedirection orthogonal to the axial direction. The main body accommodatingportion 78 is formed from the second arm 77 to the base portion 71. Themain body accommodating portion 78 includes a top surface 78 a and abottom surface 78 b which extend in the vertical plane of the rotationaxis O, and a side surface 78 c which extends in the axial direction.The top surface 78 a is formed in a planar shape which faces downward inthe axial direction. The bottom surface 78 b is formed in a planar shapewhich faces upward in the axial direction. The top surface 78 a and thebottom surface 78 b extend parallel to each other. The side surface 78 cis formed by, for example, a flat surface and a curved surface. The sidesurface 78 c extends to surround the support shaft insertion hole 72when seen in the axial direction.

As shown in FIG. 6, the knocker 70 further includes a contact portion82. The contact portion 82 protrudes from the base portion 71 in adirection orthogonal to the axial direction. The contact portion 82extends forward and inward in the vehicle width direction from the baseportion 71 when seen in the vertical direction. A tip end portion of thecontact portion 82 is in contact with a portion of the piston holdingportion 117 of the lever holder 110 which faces downstream in theoperation direction G. Rotation of the knocker 70 in a directionopposite to the operation direction G is restricted by bringing thecontact portion 82 into contact with the piston holding portion 117.That is, when the contact portion 82 is in contact with the pistonholding portion 117, the knocker 70 is located at an end portion of arotation range on the upstream side in the operation direction G.

As shown in FIGS. 6 and 8, the lever body 60 includes the rotation baseportion 61 supported by the support shaft 90, and an operating portion63 which extends from the rotation base portion 61 toward the front ofthe left grip portion 5 a. The rotation base portion 61 is inserted intothe main body accommodating portion 78 of the knocker 70 and issandwiched by the knocker 70 from both sides in the axial direction. Therotation base portion 61 is slidably in close contact with the topsurface 78 a of the main body accommodating portion 78 of the knocker70. The rotation base portion 61 is in close contact with the bottomsurface 78 b of the main body accommodating portion 78 of the knocker 70via a leaf spring 108 of the adjustment mechanism 100 described later.Thus, the rotation base portion 61 is in close contact with the knocker70 directly or via another member at a plurality of locations in theaxial direction. A support shaft insertion hole 65 is formed in therotation base portion 61. The support shaft insertion hole 65 passesthrough the rotation base portion 61 along the rotation axis O. Thesupport shaft insertion hole 65 is formed in a circular shape when seenin the axial direction.

As shown in FIG. 6, the operating portion 63 extends outward from afront portion of the rotation base portion 61 in the vehicle widthdirection. An inner end portion of the operating portion 63 in thevehicle width direction faces the contact portion 82 of the knocker 70at a distance from the downstream side in the operation direction G. Areturn spring accommodating portion 67 is formed at the inner endportion of the operating portion 63 in the vehicle width direction. Thereturn spring accommodating portion 67 is formed on a side surface whichfaces upstream in the operation direction G. The return springaccommodating portion 67 is a recessed portion which opens upstream inthe operation direction G. The return spring accommodating portion 67 isformed at a position at which it faces the contact portion 82 of theknocker 70. A return spring 86 which is a compression coil spring isinserted into the return spring accommodating portion 67. The returnspring 86 biases the lever body 60 with respect to the knocker 70 in theoperation direction G.

An adjustment mechanism 100 is interposed between the lever body 60 andthe knocker 70. The adjustment mechanism 100 is a mechanism whichadjusts a grip distance between the grip portion 5 a and the lever body60. The adjustment mechanism 100 includes an adjustment pin 101rotatably installed on the second arm 77 of the knocker 70, a camcontact member 106 installed on the lever body 60, and the leaf spring108 assembled to the adjustment pin 101.

As shown in FIGS. 6 and 8, the adjustment pin 101 is provided to berotatable around an axis parallel to the axial direction. The adjustmentpin 101 includes a cam clutch portion 102 disposed in the main bodyaccommodating portion 78 of the knocker 70, a shaft portion 103 whichextends from the cam clutch portion 102 to both sides in the axialdirection, and an operation dial 104 provided on the shaft portion 103.The cam clutch portion 102 is disposed downstream in the operationdirection G with respect to the operating portion 63 of the lever body60. The cam clutch portion 102 is formed in a polygonal shape (apentagonal shape in the embodiment) when seen in the axial direction.The cam clutch portion 102 has a plurality of (five in the embodiment)cam surfaces 102 a on the outer periphery thereof. The plurality of camsurfaces 102 a are provided at different distances from a center axis ofthe adjustment pin 101. The shaft portion 103 is rotatably supported bythe second arm 77 of the knocker 70 on both the upper and lower sideswith the cam clutch portion 102 interposed therebetween. The operationdial 104 is provided at an upper end portion of the shaft portion 103.The operation dial 104 is disposed along an upper surface of the secondarm 77 of the knocker 70. The operation dial 104 can be rotated by anoccupant.

As shown in FIG. 6, the cam contact member 106 is a member having a camcontact surface 106 a which is in contact with the cam surface 102 a ofthe cam clutch portion 102. The cam contact surface 106 a is in contactwith any one of the plurality of cam surfaces 102 a of the cam clutchportion 102 from the upstream side in the operation direction G. Thus,the lever body 60 engages with the knocker 70. Since the lever body 60is biased in the operation direction G by the return spring 86, thelever body 60 always engages with the knocker 70.

As shown in FIGS. 6 and 8, the leaf spring 108 has a bifurcated armformed at a tip end thereof and a hole formed at a base end thereofthrough which the support shaft 90 is inserted. The base end of the leafspring 108 is sandwiched between the rotation base portion 61 of thelever body 60 and the bottom surface 78 b of the main body accommodatingportion 78 of the knocker 70. The tip end of the leaf spring 108 isdisposed between the cam clutch portion 102 and the bottom surface 78 bof the main body accommodating portion 78 of the knocker 70. Thebifurcated arm at the tip end of the leaf spring 108 is disposed tosandwich the shaft portion 103. The leaf spring 108 biases theadjustment pin 101 upward in the axial direction with respect to theknocker 70.

As shown in FIG. 8, the support shaft 90 is a bolt having a screw shaft91 provided at a tip thereof. The support shaft 90 is inserted into thethrough hole 113 a of the lever holder 110 and the support shaftinsertion holes 72 and 65 of the clutch lever 51 from below. The screwshaft 91 protrudes above the lever holder 110. The support shaft 90supports the lever body 60 to be relatively rotatable. The support shaft90 supports the knocker 70 so that the knocker 70 cannot rotaterelatively. A stepped surface 92 which faces upward in the axialdirection is formed on an outer peripheral surface of the support shaft90. The stepped surface 92 extends along a vertical surface of therotation axis O.

The support shaft 90 is installed on the lever holder 110 by screwing anut 93 onto the screw shaft 91. The stepped surface 92 of the supportshaft 90 is in contact with the top surface 78 a of the main bodyaccommodating portion 78 of the knocker 70 as a seating surface. The nut93 is fastened to the base portion 71 of the knocker 70 via acylindrical first spacer 94 externally inserted onto an upper portion ofthe support shaft 90. Thus, the base portion 71 of the knocker 70 isfixed to the support shaft 90 by a fastening force of the nut 93 in astate in which it is sandwiched between the stepped surface 92 of thesupport shaft 90 and the first spacer 94. The upper portion of thesupport shaft 90 is slidably supported by the upper support portion 114of the lever holder 110 via a first bush 95 externally inserted onto thefirst spacer 94. The lower portion of the support shaft 90 is slidablysupported by the lower support portion 115 of the lever holder 110 via acylindrical second spacer 96 externally inserted onto the lower portionof the support shaft 90 and a second bush 97 externally inserted ontothe second spacer 96.

Rotation Sensor

The rotation sensor 160 converts an operation amount of the clutch lever51 into an electric signal and outputs the electric signal. For example,the rotation sensor 160 is a so-called potentiometer. The rotationsensor 160 is disposed below the lever body 60. The rotation sensor 160is installed on the lever holder 110. The rotation sensor 160 isfastened to the rotation sensor holding portion 124 with a bolt or thelike in a state in which part of the rotation sensor 160 is insertedinto the recessed portion 124 a of the rotation sensor holding portion124. The rotation detector 161 of the rotation sensor 160 is disposedcoaxially with a rotation center (the rotation axis O) of the clutchlever 51 and is integrally rotatably connected to a lower end portion ofthe support shaft 90. The rotation sensor 160 detects a rotation angleof the knocker 70 which rotates integrally with the support shaft 90 bydetecting a rotation angle of the support shaft 90. Since the knocker 70rotates integrally with the lever body 60, the rotation sensor 160 candirectly detect the operation amount of the clutch lever 51. Theoperation amount of the clutch lever 51 detected by the rotation sensor160 is input to the ECU 40.

Operation of Clutch Lever Device

Next, an operation of the clutch lever device of the embodiment will bedescribed with reference to FIG. 9.

FIG. 9 is an operation explanatory view of the clutch lever device ofthe first embodiment, and is a partial cross-sectional view of theclutch lever device when seen from above.

When the power transmission of the clutch device 26 is cut off, thelever body 60 is operated to rotate in the operation direction G withrespect to the pre-operation position. When the lever body 60 rotates inthe operation direction G, the knocker 70 which engages with the leverbody 60 also rotates in the operation direction G together with thelever body 60. When the knocker 70 rotates in the operation direction G,the roller 80 is displaced in the operation direction G and presses thepiston 133 in the first direction L1 while rolling on the tip endsurface 138 of the piston 133. The reactive force generation device 130contracts when the piston 133 is pressed in the first direction L1.

The piston 133 is biased in the second direction L2 by the spring 151.Therefore, a force in a direction opposite to the operation direction Gacts on the roller 80. That is, the reactive force generation device 130presses the knocker 70 to rotate the knocker 70 in the directionopposite to the operation direction G. When the knocker 70 is pressed inthe direction opposite to the operation direction G, the lever body 60which engages with the knocker 70 is also pressed in the directionopposite to the operation direction G. Thus, an operation reactive forceis generated on the lever body 60. When the occupant releases theoperation of the lever body 60, the lever body 60 rotates together withthe knocker 70 in the direction opposite to the operation direction Gand returns to the pre-operation position.

Here, when the reactive force generation device 130 expands andcontracts, an internal volume of the piston structure constituted of thecylinder 131 and the piston 133 changes. Since the air bleeding hole 139which allows communication between the inside and the outside of thepiston 133 is formed in the bottom wall 136 b of the small diameterportion 136 of the piston 133, air can be suctioned into the pistonstructure, or air inside the piston structure can be dischargedaccording to a change in the internal volume of the piston structure.

As described above, the reactive force generation device 130 of theclutch-by-wire system of the embodiment has the piston structure inwhich the air bleeding hole 139 is provided and includes a piston 133which is in contact with the clutch lever 51 and in which the airbleeding hole 139 is formed. With such a constitution, the clutch lever51 is located in the vicinity of the air bleeding hole 139 by formingthe air bleeding hole 139 in the piston 133 which comes into contactwith the clutch lever 51. Therefore, the air bleeding hole 139 isdisposed at a position at which it is difficult to access from theoutside because it is obstructed by the clutch lever 51. Therefore, itis possible to curb entry of foreign substances such as water and dustinto the piston structure through the air bleeding hole 139.

Particularly, in the embodiment, since the air bleeding hole 139 opensinto the space surrounded by the lever holder 110, it is possible toeffectively curb entry of foreign substances such as water and dust intothe piston structure, as compared with a configuration in which thepiston structure opens to the outside.

Further, the piston 133 has the tip end surface 138 which comes intocontact with the clutch lever 51 and in which the air bleeding hole 139opens. The tip end surface 138 of the piston 133 faces rearward. Withsuch a constitution, since the air bleeding hole 139 opens rearward, itis possible to curb entry of foreign substances into the pistonstructure through the air bleeding hole 139 when the vehicle istraveling, as compared with a constitution in which the air bleedinghole opens forward.

Further, the roller 80 of the clutch lever 51 rolls on the tip endsurface 138 of the piston 133 as the clutch lever 51 is operated. Withsuch a constitution, the air bleeding hole 139 is provided at a positionat which it is closer to the clutch lever 51. Therefore, the airbleeding hole 139 is disposed at a position at which it is moredifficult to access from the outside. Therefore, it is possible to curbentry of foreign substances such as water and dust into the pistonstructure through the air bleeding hole 139.

Further, the air bleeding hole 139 is formed in a region in which itcomes into contact with the roller 80. With such a constitution, sincethe air bleeding hole 139 is blocked by the roller 80 when the clutchlever 51 is operated, it is possible to curb entry of foreign substancesinto the piston structure through the air bleeding hole 139 when theclutch lever 51 is operated.

Further, the labyrinth structure which obstructs a flow of a fluidthrough the air bleeding hole 139 is formed on the piston 133. With sucha constitution, it is possible to effectively curb entry of foreignsubstances such as water and dust into the piston structure through theair bleeding hole 139.

Further, the labyrinth structure has the flow passage 142 whichcommunicates with the air bleeding hole 139 and extends spirally. Withsuch a constitution, for example, as compared with a constitution inwhich the flow passage extends linearly, it is possible to effectivelycurb advance of foreign substances, such as water or dust which hasentered the air bleeding hole 139, through the flow passage 142.Therefore, it is possible to curb entry of foreign substances into thepiston structure.

Second Embodiment

Next, a clutch lever device 250 of a second embodiment will be describedwith reference to FIGS. 10 to 14. In the second embodiment, detaileddescription of the portions having the same constitutions as those ofthe first embodiment will be omitted.

Lever Holder

FIG. 10 is a cross-sectional view of the clutch lever device of thesecond embodiment when seen from above. FIG. 11 is a perspective view ofthe clutch lever device of the second embodiment when seen from aboveand behind.

As shown in FIGS. 10 and 11, the clutch lever device 250 of the secondembodiment includes a lever holder 210 in place of the lever holder 110of the first embodiment. The lever holder 210 has a constitution inwhich a cover 226 is installed on the lever holder 110 of the firstembodiment. In the embodiment, in the lever holder 210, a membercorresponding to the lever holder 110 of the first embodiment isreferred to as a holder body 110. The cover 226 is disposed to define aspace, in which a contact portion in which the clutch lever 51 and thepiston 133 are in contact with each other is disposed, from the sideopposite to the piston holding portion 117. The cover 226 is disposed onthe side opposite to the piston holding portion 117 with the leversupport portion 113 interposed therebetween when seen in the verticaldirection and is fixed to the holder body 110 with screws or the like.The cover 226 is disposed upstream in the operation direction G withrespect to the first arm 74 and the roller 80 in the knocker 70 of theclutch lever 51. The cover 226 is formed to provide a first gap G1 withrespect to the first arm 74 and the roller 80 of the clutch lever 51 atthe pre-operation position.

FIG. 12 is a cross-sectional view of a portion corresponding to lineXII-XII of FIG. 10.

As shown in FIGS. 10 to 12, the cover 226 is formed in a rectangularshape having four sides which extend in the vertical direction or aforward and rearward direction when seen in the vehicle width direction.A rear end portion of the cover 226 is disposed to be close to a frontend portion of a surface of the fixed portion 111 which faces outward inthe vehicle width direction. The cover 226 extends forward from the rearend portion thereof along end surfaces of the upper support portion 114and the lower support portion 115 of the lever support portion 113 whichface outward in the vehicle width direction. An upper end edge 226 a ofthe cover 226 is disposed to be in contact with the upper supportportion 114 of the lever support portion 113. A lower end edge 226 b ofthe cover 226 is formed to provide a second gap G2 with respect to thelower support portion 115 of the lever support portion 113. A front endedge 226 c of the cover 226 is formed to provide a third gap G3 withrespect to an outer peripheral surface of the base portion 71 of theknocker 70 of the clutch lever 51 as a whole. The outer peripheralsurface of the base portion 71 of the knocker 70 is a surface of thebase portion 71 which faces outward in a radial direction. A maximumdistance of each of the second gap G2 and the third gap G3 is smallerthan a minimum distance of the first gap G1.

As shown in FIG. 10, an opening portion 211 into which the clutch lever51 is inserted is formed in the lever holder 210. The opening portion211 allows communication between the outside and the space in which thecontact portion in which the clutch lever 51 and the piston 133 comeinto contact with each other is disposed. The first arm 74 of theknocker 70 is inserted into the opening portion 211. In the embodiment,an opening edge 211 a of the opening portion 211 includes a frontportion 117 a of an opening edge of the piston holding portion 117 (anopening edge of the first tubular portion 118) and a front end edge 226c of the cover 226 as portions which radially face the outer peripheralsurface of the base portion 71 of the knocker 70. The front portion 117a of the opening edge of the piston holding portion 117 is a frontopening edge of the opening portion 211. The front end edge 226 c of thecover 226 is a rear opening edge of the opening portion 211.

As shown in FIG. 12, the lever holder 210 has a lower surface 210 awhich defines the space, in which a contact portion in which the clutchlever 51 and the piston 133 come into contact with each other isdisposed, from below. In the embodiment, the lower surface 210 a is anupper surface of the lower support portion 115 of the lever supportportion 113. A communication portion 212 which allows communicationbetween the inside and outside of the lever holder 210 is formed at anouter end portion of the lower surface 210 a in the vehicle widthdirection. The communication portion 212 is the above-described secondgap G2. The lower surface 210 a is inclined with respect to thehorizontal direction to descend toward the communication portion 212. Anouter end portion of the lower surface 210 a in the vehicle widthdirection is lowered by one step via a stepped surface which extends inthe vertical direction. The outer end portion of the lower surface 210 ain the vehicle width direction is inclined at a larger angle withrespect to the horizontal direction than the other portions of the lowersurface 210 a.

Clutch Lever

As shown in FIG. 10, the base portion 71 of the knocker 70 of the clutchlever 51 includes a facing surface 71 a which radially faces the openingedge 211 a of the opening portion 211 of the lever holder 210. Thefacing surface 71 a has a first facing surface 271 which faces the frontportion 117 a of the opening edge of the piston holding portion 117, anda second facing surface 272 which faces the front end edge 226 c of thecover 226.

FIG. 13 is a cross-sectional view of a clutch lever device of the secondembodiment when seen from above and shows in a state in which the clutchlever is completely gripped. FIG. 14 is a perspective view of the clutchlever device of the second embodiment when seen from above and in front.

As shown in FIGS. 10, 13 and 14, the first facing surface 271 isprovided downstream in the operation direction G with respect to thefirst arm 74 of the knocker 70. The first facing surface 271continuously faces the front portion 117 a of the opening edge of thepiston holding portion 117 from a state in which the clutch lever 51 isnot being operated to a state in which the clutch lever 51 is beingoperated. Specifically, the first facing surface 271 is provided from alocation at which it faces the front portion 117 a of the opening edgeof the piston holding portion 117 in a state in which the clutch lever51 is in the pre-operation position to a location at which it faces thefront portion 117 a of the opening edge of the piston holding portion117 in a state in which the clutch lever 51 is completely gripped. Thefirst facing surface 271 is formed to provide a fourth gap G4 withrespect to the front portion 117 a of the opening edge of the pistonholding portion 117. The first facing surface 271 extends in an arcshape centered on the rotation axis O when seen in the axial direction.In the embodiment, the first facing surface 271 extends with a constantcurvature about the rotation axis O. Thus, the first facing surface 271keeps a distance of the fourth gap G4 constant regardless of the amountof operation of the clutch lever 51. A maximum distance of the fourthgap G4 is smaller than the minimum distance of the first gap G1.

As shown in FIGS. 10, 11 and 13, the second facing surface 272 isprovided upstream the operation direction G with respect to the firstarm 74 of the knocker 70. The second facing surface 272 continuouslyfaces the front end edge 226 c of the cover 226 from the state in whichthe clutch lever 51 is not being operated to the state in which theclutch lever 51 is being operated. Specifically, the second facingsurface 272 is provided from a location at which it faces the front endedge 226 c of the cover 226 in the state in which the clutch lever 51 isin the pre-operation position to a location at which it faces the frontend edge 226 c of the cover 226 in the state where the clutch lever 51is completely gripped. The second facing surface 272 is formed toprovide the above-described third gap G3 with respect to the front endedge 226 c of the cover 226. The second facing surface 272 extends in anarc shape centered on the rotation axis O when seen in the axialdirection. In the embodiment, the second facing surface 272 extends witha constant curvature about the rotation axis O. Thus, the second facingsurface 272 keeps the distance of the third gap G3 constant regardlessof the amount of operation of the clutch lever 51.

The clutch lever device 250 of the above-described embodiment exhibitsthe following effects in addition to the same effects as those in thefirst embodiment.

In the embodiment, the opening portion 211 into which the clutch lever51 is inserted is formed in the lever holder 210. The clutch lever 51has the facing surface 71 a which radially faces the opening edge 211 aof the opening portion 211. The facing surface 71 a continuously facesthe opening edge 211 a of the opening portion 211 from the state inwhich the clutch lever 51 is not being operated to the state in whichthe clutch lever 51 is being operated, and extends in an arc shapecentered on the rotation axis O when seen in the axial direction. Withsuch a constitution, the distance of each of the gaps G3 and G4 betweenthe clutch lever 51 and the opening edge 211 a of the lever holder 210can be kept constant regardless of the amount of operation of the clutchlever 51. Thus, it is possible to curb easy entry of foreign substancesinto the lever holder 210 by operating the clutch lever 51 as the gapbetween the clutch lever 51 and the opening edge 211 a of the leverholder 210 changes. Therefore, it is possible to curb occurrence ofdefects such as biting of foreign substances.

Further, the facing surface 71 a has a first facing surface 271 whichfaces the front opening edge of the opening portion 211 (the frontportion 117 a of the opening edge of the piston holding portion 117).With such a constitution, it is possible to effectively curb entry offoreign substances or the like approaching the lever holder 210 from theside in front into the lever holder 210, for example, when the vehicleis traveling.

Further, the lever holder 210 includes a lower surface 210 a whichdefines a space, in which a contact portion where the clutch lever 51and the piston 133 come into contact is disposed, from below. Thecommunication portion 212 which allows communication between the insideand outside of the lever holder 210 is formed in the lower surface 210a. The lower surface 210 a is inclined to descend toward thecommunication portion 212. With such a constitution, foreign substanceswhich have entered the space in which the contact portion in which theclutch lever 51 and the piston 133 come into contact with each other isdisposed can be smoothly guided to the communication portion 212 by aninclination of the lower surface 210 a of the lever holder 210.Therefore, even when foreign substances have entered the inside of thelever holder 210, the foreign substances can be effectively dischargedthrough the communication portion 212, and occurrence of defects such asthe biting of the foreign substances can be curbed.

Third Embodiment

Next, a clutch lever device 350 of a third embodiment will be describedwith reference to FIG. 15. In the third embodiment, detailed descriptionof the portions having the same constitutions as those of the firstembodiment will be omitted.

Reactive Force Generation Device

FIG. 15 is an enlarged cross-sectional view of the clutch lever deviceof the third embodiment.

As shown in FIG. 15, the reactive force generation device 330 of thethird embodiment is different from the reactive force generation device130 of the first embodiment in that it includes an adjuster 360 foradjusting a biasing force of the spring 151. The adjuster 360 isprovided on a bottom wall of the cylinder 131. Specifically, theadjuster 360 is formed in a cylindrical shape and is tightly insertedinto a through hole formed in the bottom wall of the cylinder 131. Afemale screw is formed in the through hole of the bottom wall of thecylinder 131, a male screw is formed on an outer peripheral surface ofthe adjuster 360, and the adjuster 360 is screwed to the bottom wall ofthe cylinder 131. For example, a groove into which a driver or the likeis inserted is formed in an end surface of the adjuster 360 in the firstdirection L1. The adjuster 360 can be displaced in the first directionL1 and the second direction L2 with respect to the cylinder 131 byrotating with respect to the bottom wall of the cylinder 131. The firstseat 152 is in contact with an end surface of the adjuster 360 in thesecond direction L2. The adjuster 360 is pressed against the end portionof the spring 151 in the first direction L1 via the first seat 152. Theadjuster 360 can adjust the biasing force of the spring 151 by beingdisplaced with respect to the cylinder 131 in the first direction L1 orthe second direction L2 and causing the end portion of the spring 151 inthe first direction L1 to be close to or far away from the end portionof the spring 151 in the second direction L2.

The clutch lever device 350 of the above-described embodiment exhibitsthe following effects in addition to the same effects as those of thefirst embodiment.

In the embodiment, the reactive force generation device 330 includes theadjuster 360 which causes the end portion of the spring 151 in the firstdirection L1 to be close to or far away from the end portion thereof inthe second direction L2. With such a constitution, the adjuster 360 canchange a length between both end portions of the spring 151 to adjust aforce for pressing the piston 133. Therefore, it is possible to providethe reactive force generation device 330 which can freely change thereactive force applied to the clutch lever 51.

The present invention is not limited to the above-described embodimentsdescribed with reference to the drawings, and various modified examplescan be considered within the technical scope thereof.

For example, in the above-described embodiment, the second tubularportion 119 of the piston holding portion 117 of the lever holder 110also serves as the cylinder 131 of the reactive force generation device130. However, the present invention is not limited thereto. The cylinderof the reactive force generation device may be formed separately fromthe piston holding portion 117 of the lever holder 110, and may bedisposed inside the piston holding portion 117 of the lever holder 110.

Further, in the above-described embodiment, in the reactive forcegeneration device 130, the intermediate tube 144 is disposed between theinner peripheral surface of the cylinder 131 and the outer peripheralsurface of the piston 133. However, the present invention is not limitedthereto, and the piston may be in direct sliding contact with thecylinder.

Further, in the above-described embodiment, the reactive forcegeneration device 130 is formed so that the piston 133 is displaced withrespect to the fixedly provided cylinder 131. However, the presentinvention is not limited thereto. For example, the reactive forcegeneration device may be formed so that the cylinder externally insertedonto the piston and in contact with the knocker 70 is displaced withrespect to the fixedly provided piston. In this case, the same effectsas those of the above-described embodiment can be obtained by providingthe air bleeding hole in the cylinder.

Further, in the above-described embodiment, the flow passage 142 havingthe labyrinth structure is constituted of the first labyrinth groove 142a and the second labyrinth groove 142 b in the outer surface of thelabyrinth member 141. However, the present invention is not limitedthereto, and for example, the flow passage having the labyrinthstructure may be formed by a groove formed in the inner surface of thesmall diameter portion of the piston 133.

Further, in the above-described embodiment, the clutch lever 51 includesthe lever body 60 and the knocker 70 as separate members. However, thepresent invention is not limited thereto, and the clutch lever may beone member in which the lever body 60 and the knocker 70 are integrated.

Further, in the above-described embodiment, a so-called normally opentype which is in a connected state in which power can be transmitted bysupplying a hydraulic pressure in a normally disconnected manner hasbeen exemplified as a clutch device. However, the clutch device is notlimited to the normally open type. That is, the clutch device may be aso-called normally closed type which is in a disconnected state in whichpower cannot be transmitted by supplying a hydraulic pressure in anormally connected manner.

In addition, it is possible to replace the components in theabove-described embodiments with well-known components as appropriatewithout departing from the spirit of the present invention, and theabove-described embodiments and modified examples may be appropriatelycombined. For example, the lever holder 210 of the second embodiment maybe combined with the adjuster 360 of the third embodiment.

REFERENCE SIGNS LIST

51 Clutch lever

71 a Facing surface

80 Roller

117 a Front portion of opening edge (opening edge)

130, 330 Reactive force generation device

131 Cylinder (holding member)

133 Piston (contact member)

139 Air bleeding hole

138 Tip end surface (contact surface)

142 Flow passage

151 Spring (coil spring)

210 Lever holder

210 a Lower surface

211 Opening portion

211 a Opening edge

212 Communication portion

360 Adjuster

O Rotation axis

What is claim is:
 1. A reactive force generation device of aclutch-by-wire system which generates a reactive force on a clutchlever, comprising: a piston structure in which an air bleeding hole isprovided; and a contact member which is in contact with the clutch leverand in which the air bleeding hole is formed.
 2. The reactive forcegeneration device according to claim 1, wherein: the contact member hasa contact surface which comes into contact with the clutch lever and inwhich the air bleeding hole opens, and the contact surface faces a rearof a vehicle.
 3. The reactive force generation device according to claim1, wherein: the contact member has a contact surface which comes intocontact with a roller of the clutch lever and in which the air bleedinghole opens, and the roller rolls on the contact surface according to anoperation of the clutch lever.
 4. The reactive force generation deviceaccording to claim 3, wherein the air bleeding hole is formed in aregion in which the roller comes into contact.
 5. The reactive forcegeneration device according to claim 1, wherein a labyrinth structurewhich obstructs a flow of a fluid through the air bleeding hole isformed on the contact member.
 6. The reactive force generation deviceaccording to claim 5, wherein the labyrinth structure has a flow passagewhich communicates with the air bleeding hole and extends spirally. 7.The reactive force generation device according to claim 1, comprising: aholding member which holds the contact member and constitutes a pistonstructure together with the contact member; a coil spring which isinterposed between the contact member and the holding member presses thecontact member at a first end portion thereof; and an adjuster which isprovided on the holding member and causes a second end portion of thecoil spring to come closer to and separate from the first end portion.8. A clutch lever device which comprises the reactive force generationdevice of the clutch-by-wire system according to claim 1, comprising: aclutch lever which rotates around a rotation axis and to which areactive force is applied by the reactive force generation device; and alever holder which rotatably supports the clutch lever and surrounds acontact portion in which the clutch lever and the contact member comeinto contact with each other, wherein an opening portion into which theclutch lever is inserted is formed in the lever holder, the clutch leverhas a facing surface which faces an opening edge of the opening portionin a direction orthogonal to the rotation axis, and the facing surfacecontinuously faces the opening edge of the opening portion from a statein which the clutch lever is not being operated to a state in which theclutch lever is being operated, and extends in an arc shape centered onthe rotation axis when seen in a direction in which the rotation axisextends.
 9. The clutch lever device according to claim 8, wherein thefacing surface faces a front opening edge of the opening portion.
 10. Aclutch lever device which comprises the reactive force generation deviceof the clutch-by-wire system according to claim 1, comprising: a clutchlever which rotates around a rotation axis and to which a reactive forceis applied by the reactive force generation device; and a lever holderwhich rotatably supports the clutch lever and surrounds a contactportion in which the clutch lever and the contact member come intocontact with each other, wherein the lever holder includes a lowersurface which defines from below a space in which a contact portion inwhich the clutch lever and the contact member come into contact witheach other is disposed, a communication portion which allowscommunication between an inside and an outside the lever holder isformed in the lower surface, and the lower surface is inclined todescend toward the communication portion.